• Journal of the Korean Chemical Society
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• 제34권6호
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• pp.517-526
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• 1990

The crystal structures of two alditol acetates, D-glucitol hexaacetate and xylitol pentaacetate, have been determined by diffraction methods with Mo-K$\alpha$radiation, using direct methods for phase determinations. The crystal data are: for D-glucitol hexaacetate, P2$_1$, with a = 10.275 (2), b = 8.363 (1), c = 12.560 (5) $\AA;\beta$ = 95.97 $(2)^{\circ}$, Z = 2; for xylitol pentaacetate, P2$_1$/C with a = 18.126 (1), b = 11.422 (2), c = 8.649 (1) $\AA$, $\beta = 95.03 (1)^{\circ}$, Z = 4. Both molecules have extended zigzag carbon chain conformations which differ from previous studies of the structures of D-glucitol and xylitol and also differ from NMR studies on alditol acetates. The bond lengths and angles are normal, with mean values over both structures of C($sp^3)-C(sp^3): 1.514 (10),\; C(sp^3)-O: 1.444 (6),\; C(sp^2)-O: 1.347 (9),\; C(sp^2)=O: 1.197 (6),\; C(sp^2)-C(sp^3): 1.479(9){\AA},\; C(sp^3)-C(sp^3)-C(sp^3): 114.6 (17),\; O-C(sp^3)-C(sp^3): 109.4 (23),\; C(sp^2)-O-C(sp^3): 117.4 (6),\; O=C(sp^2)-O: 122.6 (6),\; C(sp^3)-C(sp^2)-O: 111.8 (7),\; C(sp^3)-C(sp^2)=O: 125.5 (4)^{\circ}$. The atoms of acetate groups are in coplanar. There are no particularly short intermolecular contacts and the molecules are held together by van der Waals force only.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.113-113
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• 2009

This paper describes the characteristics of a poly 3C-SiC micro heater which was fabricated on $AlN(0.1{\mu}m)/3C-SiC(1.0{\mu}m)$ suspended membranes by surface micro- machining technology. The 3C-SiC and AlN thin films which have wide energy bandgap and very low lattice mismatch were used sensors for high temperature and voltage environments. The 3C-SiC thin film was used as micro heaters and temperature sensor materials simultaneously. The implemented 3C-SiC RTD (resistance of temperature detector) and the power consumption of micro heaters were measured and calculated. The TCR (thermal coefficient of the resistance) of 3C-SiC RTD is about -5200 $ppm/^{\circ}C$ within a temperature range from $25^{\circ}C$ to $50^{\circ}C$ and -1040 $ppm/^{\circ}C$ at $500^{\circ}C$. The micro heater generates the heat about $500^{\circ}C$ at 10.3 mW. Moreover, durability of 3C-SiC micro heaters in high voltages is better than pt micro heaters. A thermal distribution measured and simulated by IR thermovision and COMSOL is uniform on the membrane surface.

• Journal of the Korean Ceramic Society
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• 제38권4호
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• pp.314-318
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• 2001

SiC-TiC composites have been fabricated by using a mechanochemical processing of a mixture of Si, Ti, and C at room temperature and subsequent hot pressing. TiC powders have been obtained by the mechanochemical processing of a mixture of Ti and C whereas SiC powders has not been obtained from a mixture of Si and C. By using the exothermic reaction between Ti and C, SiC-TiC powder could be obtained from the mixture of Si, Ti, and C using the mechanochemical processing for more than 12h. The X-ray diffraction analysis has shown that the powder subjected to the mechanochemical processing consisted of the particles having crystallite size below 10nm. Fully densified SiC-TiC composites have been obtained by hot-pressing of the powder at 1850$\^{C}$ for 3h and it has shown comparable mechanical properties to those of the SiC-TiC composites prepared from the commercially available SiC and TiC powders. Flexural strength of 560 MPa and fracture toughness of 4.8 MP$.$am$\_$1/2/ have been shown for the SiC-TiC composites with composition corresponding to 0.75:0.25:1 mole ratio of Si:Ti:C.

• Journal of Sensor Science and Technology
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• 제18권4호
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• pp.311-315
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• 2009

This paper describes the characteristics of a poly 3C-SiC micro heater which was fabricated on AlN(0.1 $\mu$m)/3C-SiC(1.0 $\mu$m) suspended membranes by surface micro-machining technology. The 3C-SiC and AlN thin films which have wide energy band gap and very low lattice mismatch were used sensors for high temperature and voltage environments. The 3C-SiC thin film was used as micro heaters and temperature sensor materials simultaneously. The implemented 3CSiC RTD(resistance of temperature detector) and the power consumption of micro heaters were measured and calculated. The TCR(thermal coefficient of the resistance) of 3C-SiC RTD is about -5200 ppm/$^{\circ}C$ within a temperature range from 25 $^{\circ}C$ to 50 $^{\circ}C$ and -1040 ppm/$^{\circ}C$ at 500 $^{\circ}C$. The micro heater generates the heat about 500 $^{\circ}C$ at 10.3 mW. Moreover, durability of 3C-SiC micro heaters in high voltages is better than Pt micro heaters. A thermal distribution measured and simulated by IR thermovision and COMSOL is uniform on the membrane surface.

• Journal of agriculture & life science
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• 제44권6호
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• pp.79-82
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• 2010

Three types of leaf domatia; Pocket (P), Tufts (T) and Tufts-Pocket (TP) were observed in the five species of Cornus namely; Cornus kousa, C. controversa, C. officinalis, C. walteri and C. alba. In C. walteri no tufts were observed, the domatia was just a well developed pocket one. In C. officinalis and C. kousa, tufts domatia of brownish color were observed but C. officinalis developed denser tufts than those observed in C. kousa. Unlike in C. kousa where the domatia covered about only 1/2 of the axil, in the C. officinalis tufts covered almost 3/4 of the axil. In both species the tufts domatia were located in the inner side of the leaf axil. In C. controversa and C. alba whitish colored tufts were observed covering Pockets and hence the Tuft Pocket domatia. In C. controversa the tufts were more than in C. alba but in both species the tufts were short and were located in the inner sides of the axil. Thus, based on these physiological features it was concluded that C. officinalis and C. kousa are sister species likewise C. controversa and C. alba while C. walteri belong to another lineage. The advancement of domatia (absence of tufts) in C. walteri suggests that they are the most advanced while C. officinalis and C. kousa the most primitive due to their possession of highly developed tufts and C. controversa and C. alba the intermediates.

• Korean Journal of Agricultural Science
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• 제25권2호
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• pp.181-198
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• 1998

In order to determine the optimum pasteurization conditions by microwave heating(MWH) at $50^{\circ}C{\sim}70^{\circ}C$ for 30 minute compared with water bath heating(WBH) at $65^{\circ}C$ for 30minute during storage at $5^{\circ}C$, the chemical composition, microbiological changes and keeping quality were examined and the results were as follows: 1. The fat protein lactose, total solid contents of raw milk, at $50{\sim}70^{\circ}C$ for 30 min. in MWH and at 65 for $30^{\circ}C$ min. in WBH did not changed significantly during the storage at $5^{\circ}C$. 2. The pH and acidity for the raw milk untreated were 6.75 and 0.16%, and those of MWH heated and WBH milk wee 6.75~6.50 and 0.16%~0.19%, phosphatase test were negative at $61^{\circ}C$ for 20 min. at $62^{\circ}C$ for 15 min. at $63^{\circ}C$ for 10 min. at $64^{\circ}C$ for 5 min. at $65^{\circ}C$ for 5 min. in MWH and at $65^{\circ}C$ for 30 min. in WBH. 3. Whey protein content was $18.53mg/m{\ell}$ in raw milk untreated, however, those were decreased as the heating temperature increased. The proteolytic activity of treated milk by WBH(44%) was lower than that by MWH(94%). 4. Total bacteria counts were $2.8{\times}10^5CFU/m{\ell}$ in raw milk untreated, $2.8{\times}10^3CFU/m{\ell}$ at $65^{\circ}C$ for 30 min. $2.4{\times}10^3CFU/m{\ell}$ at $70^{\circ}C$ for 30 min. in MWH and $3.0{\times}10^3CFU/m{\ell}$ at $65^{\circ}C$ for 30 min. in WBH. Because total bacteria count did not increased in MWH at $65^{\circ}C$, $70^{\circ}C$ for 30 min. and $65^{\circ}C$ for 30 min. in WBH during the 10 days storaging, Also, total bacteria counts for treated milk were a most drastic decrease after $61^{\circ}C$, $62^{\circ}C$, $63^{\circ}C$, $64^{\circ}C$, $65^{\circ}C$ for 5 min. in MWH. 5. Coliform bacteria counts were $2.6{\times}10^3CFU/m{\ell}$ in raw milk untreated. There were not detected at $55^{\circ}C{\sim}70^{\circ}C$ for 30 min. in MWH and at $65^{\circ}C$ for 30 min. in WBH. Coliform bacteria counts were not detected after $61^{\circ}C$, $62^{\circ}C$, $63^{\circ}C$, $64^{\circ}C$, $65^{\circ}C$ for 5 min. in MWH. 6. Thermoduric bacteria counts were $5.2{\times}10^4CFU/m{\ell}$ in raw milk untreated, $2.0{\times}10^3CFU/m{\ell}$ at $65^{\circ}C$ for 30 min. $1.9{\times}10^3CFU/m{\ell}$ at $70^{\circ}C$ for 30min. in MWH and $2.2{\times}10^3CFU/m{\ell}$ at $65^{\circ}C$ for 30 min. in WBH. Because thermoduric bacteria counts did not increased in MWH at $65^{\circ}C$, $70^{\circ}C$ for 30 min. and $65^{\circ}C$ for 30 min. in WBH during the 10days storaging. Also, thermoduric bacteria counts were a most drastic decrease after $61^{\circ}C$, $62^{\circ}C$, $63^{\circ}C$, $64^{\circ}C$, $65^{\circ}C$ for 5 min. in MWH. 7. Psychrotrophic bacteria counts were $2.8{\times}10^5CFU/m{\ell}$ in raw milk untreated, $2.0{\times}10^1CFU/m{\ell}$ at $65^{\circ}C$ for 30 min. $2.0{\times}10^1CFU/m{\ell}$ at $70^{\circ}C$ for 30 min. in MWH and $3.0{\times}10^1CFU/m{\ell}$ at $65^{\circ}C$for 30 min. in WBH. Because psychrotrophic bacteria counts did not increased in MWH at $65^{\circ}C$, $70^{\circ}C$ for 30min. and $65^{\circ}C$ for 30 min. in WBH during the 10 days storaging. Also, psychrotrophic bacteria counts were a most drastic decrease after $61^{\circ}C$, $62^{\circ}C$, $63^{\circ}C$, $64^{\circ}C$, $65^{\circ}C$ for 5 min. in MWH.

• Korean Journal of Food Science and Technology
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• 제15권1호
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• pp.66-69
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• 1983

Triglyceride fraction was separated from olive oil by thin layer chromatography (TLC) and fractionated into four groups by high performance liquid chromatography (HPLC). Compositions of the triglycerides and fatty acids of four fractions were determined by gas liquid chromatography (GLC). The olive oil contained higher concentrations of C-52 and C-54 triglycerides having partition numbers of 48. The fatty acid compositions of these triglycerides were mainly composed of C18:1 and C18:2 fatty acids. From these results, the possible fatty acid combinations of major triglycerides of olive oil were estimated to be(3C18:1;50.6%), (1C16:0, 2C18:1;23.51%), (2C18:1, 1C18:2;5.48%), (1C18:0, 2 18:1;4.55%), (1C16:0, 1C18:1, 1C18:2;2.94%), (2C16:0, 1C18:1;2.35%), (1 C16:1, 2 C18:1;2.21%), (1C18:1, 2C18:2;1.06%), (1 C14:0, 2 C18:1;1.03%).

• Journal of the Korean Society of Food Science and Nutrition
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• 제13권3호
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• pp.263-267
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• 1984

The present study was conducted to elucidate the triglyceride composition of walnut oil. The triglycerides were separated by thin layer chromatography (TLC) and fractionated on the basis of partition numbers by reverse phase high performance liquid chromatography (HPLC) on a column packed with $\mu$-bondapak $C_{18}$ using methanol-chloroform mixture as a solvent system. Each of these collected fractions was fractionated again on the basis of acyl carbon number of triglyceride by gas liquid chromatography (GLC). The fatty acid composition of triglycerides for each partition numbered group was also analyzed by GLC. From the results, it was found that walnut oil consists of ten kinds of triglycerides, and the patterns of major ones in walnut oil were as follows: 53.3% of $(C_{18:2},\;C_{18:2},\;C_{18:2})$, 10.1% of $(C_{18:1},\;C_{18:2},\;C_{18:2})$, 5.4% of $(C_{18:1},\;C_{18:1},\;C_{18:2})$, 4.3% of $(C_{18:1},\;C_{18:2},\;C_{18:3})$, 3.9% of $(C_{18:0},\;C_{18:2},\;C_{18:2})$, 2.0% of $(C_{18:0},\;C_{18:1},\;C_{18:2})$, 1.8% of $(C_{18:0},\;C_{18:2},\;C_{18:2})$.

• Analytical Science and Technology
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• 제21권3호
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• pp.212-221
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• 2008

In order to investigate the information for effective detection and developing of latent fingerprints, we identified fatty acids composition of latent fingerprints on non-porous evidence surface and the chemical changes of latent fingerprint residue after print deposition during 7 months. Fingerprints from eight Korean male donors (aged 29-50 years) and one female donor (aged 36 years) were collected. All fingerprints were found to contain lauric acid (C12:0), myristic acid (C14:0), palmitic acid (C16:0), stearic acid (C18:0), elaidic acid (C18:1n9t), oleic acid (C18:1n9c), linoleic acid (C18:2n6c), arachidic acid (C20:0), linolenic acid (C18:3n3), erucic acid (C22:1n9) and docosadienoic acid (C22:2) and primarily palmitic acid (35.45-48.37%), oleic acid (14.84-28.49%), stearic acid (9.71-24.96%) and linoleic acid (7.68-18.8%) occupied 75% of total fatty acids. When the fingerprints were deposited at dark room for 7 months, total fatty acids components decreased about 12-25%. It can be explained that significant degradation of long-chain fatty acids such as elaidic acid (C18:1n9t), arachidic acid (C20:0), linolenic acid (C18:3n3), erucic acid (C22:1n9), and docosadienoic acid (C22:2) resulted in the generation of myristic acid (C14:0), myristoleic acid (C14:1) and pentadecanoic acid (C15:0).

• Journal of the Korean Ceramic Society
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• 제31권8호
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• pp.849-860
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• 1994

The microstructural evolution and crystalline phases of this infiltration of Ti+Al liquids in TiC, SiC, TiC+C, and SiC+C preforms have been investigated. As the Ti and Al mixing ratio in Ti+Al infiltrated liquid changes, the newly formed reaction products, which were reacted from the Ti+Al liquid with preforms, consisted of three major phases as Ti3AlC, Al2Ti4C2 or Al4C3. The TiC grain shape was changed to spheroid, when Ti3AlC was formed. In case of Al2Ti4C2 formation, the platelet grain was formed from the original TiC grain. When Al4C3 was formed, nodular or intergranular fine-grained Al4C3 was formed around the TiC grain, while the original TiC grain shape was not changed.